Track block



A. S. KROTZ TRACK BLOCK Jan. 2 1945.

Filed Oct. 17, 194? ENZZZL in 516F072 Patented Jan. 2, 1 945 TRACK BLOCK Alvin S. Krotz, Akron, Ohio, assignor to The B. F.

Goodrich Company, New York, N. Y., a corporation of New York Application October 17, 1942, Serial No. 462,330

8 Claims. (01. 305-10) This invention relates to track blocks for articu- 1 lated block tracks and is suitable especially for us in vehicles, such as military tanks and other endless track vehicles, wherein the weight of the vehicle is supported through bogie wheels bearing upon the blocks of the articulated block track and driving and guiding of the track are effected about other wheels.

In tracks of this type, in addition to the requirement of supplying a traction surface for the tank, the blocks are subject to severe forces as a result of the weight of the vehicle and the impact of the bogie, idler; and other wheels upon the blocks, at times so great as to distort blocks of prior constructions out of shape. Constructions proposed heretofor involving steel bracing, apertured for reducing weight, have either required so much metal as to increase the weight objectionably or have been inadequate in supplying the desired sturdy support throughout the width and length of the block. I

The chief objects of this invention are to provide great strength of the block together with minimum weight; to provide a block construction effective to resist with great strength the forces tending to bend or otherwise distort it; to provide for utilizing the advantages of hard wood or other non-metallic substance having similar stiff but slightly resilient characteristics, while at the same time providing for protection of the wood from the forces encountered; and to provide for simplicity of construction and convenience of manufacture and assembly.

These and further objects will be apparent from the following description, reference being had to the accompanying drawing in which:

Fig. 1 is a perspective view of a track block constructed in accordance with and embodying the invention.

Fig. 2. is a sectional view taken along the line 2-2 of Fig. 1.

Fig. 3 is a group perspective view of parts of the block.

, Fig. 4 is a view like Fig. 1 but showing a modifled construction.

Fig. .5 is a perspective view of a part of the block of Fig. 4.

Figs. 6 and 7 are views like Figs. 4 and 5 respectively, but showing a further modified construction, parts in Fig. 6 being sectioned and broken away.

A hollow frame structure l which may comprise steel tubing flattened to the shape shown in Figs. 1 and 3, or sheet or plate steel bent to such shape and welded at its edges, provides a top wall vll, a bottom wall l2 and curved end tacting surfaces.

- with adjacent blocks.

walls l3 and M. The top wall Il may be used as the surface upon which the bogie and other wheels ride, or a pad, indicated in broken lines at [5 and constructed of rubber, fabric or other suitable cushioning material secured to the Wall ll may be provided to supply such wheel-con- The bottom wall [2 may itself supply the traction surface of the block, or any desired tread element, indicated by broken lin s [6 may be secured to such wall, whether the tread element be in the form of a metal cleat or a block of rubber, fabric or other suitable material.

Within the frame Ill and at the curved end rial, wh ch bushings may be in the form of hollow cylinders for accommodating pins l9 and 20,. which ins project at the sides of the block for ngagement with link connectors (not shown) to connect the block in an articulatedmanner Preferably the bushings l1 and I8 and their pins I9, 20 are bonded together by vulcanization so'that rotation of the pin as a result of articulation of the track about the driving wheels will be accommodated by compulsory distortion of th resilient bushing in circular shear stress, rather than by possible slippage of the pin with respect to the resilient material. Resistance to slippage of the bushings l1 and IS with respect to the frame I0 is enhanced by maintaining the bushings in a compressed condition against the walls of the frame.

For this purpose of maintaining the bushings in a state of compression radially of the pins, and also to the end of supplying a filler for the remaining space in the frameso as to support the weight of the vehicle-through the bogie wheels riding upon the top wall, I provide a block 2| preferably substantially filling the space and of a suificient length to cause the resilient bushings to be pressed against the curved walls l3 and M of the frame. The block 2| preferably has end walls 22, 23, shaped to conform to the adjacent walls of the resilient bushings so that the compressing force is applied substantially entirely throughout the adjacent areas.

In addition to simplicity of construction and assembly this construction has been found to have the advantage of withstanding very heavy forces in use, especially the forces of the bogie and other of the vehicle wheels which have'caused distortion of blocks of prior constructions by bowing them down in the middle region and distorting the steel frame work and other parts of the prior constructions. From the result of comparative tests of construction, it appears that the superiority of the present construction to withstand the forces of use is due to the fact that the block 2| of hard wood, being substantially solid and substantially filling the space between the top and bottom walls of the frame structure and having a high degree of stifiness inherent in such material together with some degree :of lyi'eldability and resilience, is effective to resist the rolling heavy load of the bogie wheels and the shocks of impact without objectionable permanent distortion of the block. The metal of the frame and the wood of the block cooperate with each other to prevent bending of the metal and shattering of the'wood under the severe forces of use.

While hard wood such a maple has given good results for the filler block 2 l., other non-metallic materials may in some cases be used, such for example as impregnated soft or other woods, heat-setting resins and other materials of the plastic variety which may be reinforced by fabric, wire or thelike.

In the embodiment of Figs. 4 and 5, a frame 30, of flattened tubular formand which may or may not have top or bottom pad or cleat structures secured thereto, is adapted to receive resilient bushings 3! and 32 of the kind shown in Fig. 5, prior to assembly. These bushings, instead of being wholly cylindrical have a flat face 33 adapted I .to receive pressure from a filler block 34, and the bushing at its curved side against the wall of the frame has a plate 35 extending only part way around the bushing 'circumferentially of the pin and bonded as by vulcanization to the resilient material of the bushing. I'he bushing preferably is likewise bonded'to the pin 36. The compressive force on the resilient material between the pin and the-end wall of the frame structure, arisingfrom longitudinal tension in the track as well as the compressive force of the bushing resulting from the crowdingof the filler block 34, if severe, might result in objectionable creeping of the resilient material in the direction of the pin, or crosswise of the block. Such creeping is strongly resisted by the bond between the resilient material and the plate 35 as well a thepin 36. In this embodiment retaining means in the form of tabs 31, 31 in the metal of the frame structure are bent down over the sides of the wood filler block 34 to prevent outward movement of the same, although the frictional force of the tight fit is available to resist such'movement. The tabs 31, 31 'or other suitable retaining means for the wood block may be utilized to like effect in any of the herein described embodiments. plicable, if desired, to any of the embodiments described herein is the provision of bosses 38, 38 at the ends of the top wall of the frame in the region of the curved portion for the purpose of lessening the gap between adjacent blocks to increase the smoothness of the passage of this face of the track against the bogie wheels. These bosses have the advantage also of limiting the arc of pivotal movement of adjacent blocks under some conditions of handling so that undue stress will not be imposed on the resilient bushings.

The bosses may beiprovided in -any suitable manner, as by welding on pieces of metal or by pressing out projections from the metal of the frame -30.

With reference to Figs. 6 and "7 the resilient bushing 40 has a metal sleeve or shell structure H bonded to its surface, and in order that the resilient material may be compressed by a filler block 42, each bushing has its enclosing sleeve Also api pressure.

(plates '43 coextensive "with the exposed faces of the filler block may be inserted between the top and bottom walls of the frame and between the resilient bushings and secured to the frame as by welding.

In assembling the track block of any of the embodiments described herein, the resilient bushings and .pin's'may be positioned within the hollow frame structure and the filler block may be inserted by "pressing the same therein. A suitable tapered teaser block may be used in advance of the filler block to facilitate the entry under If desired, however, the filler block may be inserted first and the resilient bushings forcedin subsequently.

Variations may be made without departing from the scope of the invention as'defin'ed in the following claims.

I claim:

1. A block for an articulated block track comprising a hollow frame structure including top, bottom and end walls, spaced-apart connector members extending transversely through said frame structure, elements of resilient material embracing said connector members at said'end walls, and a substantially solid block of nonmetallic material having substantially the loadsupporting characteristics of hard wood substantially filling the space between the top and bottom walls of said structure and between said elements and compressing the latter against said end walls and against said connector members.

2. A block for an articulated block track com prising a hollow frame structure including top, bottom and end walls, spaced-apart connector members extending transversely through said frame structure, elements of resilient rubber-like material embracing said connector members at sai end walls, and a substantially solid block of wood substantially filling the space between the top and bottom walls of said structure and be tween said elements and compressing the latter against said end walls and against said connector members. I

3. A block as defined in claim '2 comprising metallic protecting plates 'at the sides of 'said end walls, and a filler structure extending between the top and bottom walls of said frame structure and between said elements and compressing the latter against said metallic plates and against'said connector members.

5. A block as defined in claim 4 in which said metallic plates to which said elements are bonded are of U-shaped cross-section and interposed between said elements and said end walls.

6. A block 'for an articulated block track com-- prising a tubular frame structure of metal in flattened form providing top and bottom flatwalls terminating in curved end walls, connectormembers extending transversely through said frame structure, elements of resilient rubber-like material embracing the connector members at said end walls, and ablock of non-metallic material having substantially the load-supporting characteristics of hard wood tightly fitting the space between said top and bottom fiat walls and between the resilient elements and compressing the latter against said end walls and against said connector members.

7. A block for an articulated block track comprising a tubular frame structure of metal in flattened form providing top and bottom flat walls terminating in curved end walls, connector members extending transversely through said frame structure, elements of resilient rubber-like material embracing the connector members at said end walls, bosses integral with the frame structure at said end walls efiective to reduce the gap between adjacent blocks, and a block of non-metallic material having substantially the load-supporting characteristics of hard wood tightly fitting the space between said top and bottom fiat Walls and between the resilient elements and co-mpressingvthe latter against said end walls and against said connector members.

8. A block for an articulated block track comprising a hollow frame including top, bottom and end walls, spaced-apart connector members extending transversely through said frame structure, elements of resilient rubber-like material embracing said connector members at said end ALVIN S. KROTZ. 

